I was curious why these guys (Kaizen Tuning) were putting together a Motul oil change kit for $70 (which I would guess is for local sale only, no shipping):
I used Mobil 1 in my E36/5 (which came with conventional oil). Used BMW synthetic with my E46s while under warranty (Royal Purple after warranty since that was what my independent shop used).
My 135 is still under warranty, and it's only been to the dealer for service. Not sure what I'll run post warranty (and I'll probably do them myself).
I plan on continuing used oil analysis on all my oil changes.